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Genome architecture and virulence gene dynamics in oat crown rust populations

Melania Figueroa: Department of Plant Pathology, University of Minnesota

<div>Crown rust caused by <em>Puccinia coronata</em> f. sp. <em>avenae</em> (<em>Pca</em>) is the most destructive foliar pathogen of cultivated oat, <em>Avena sativa</em>. Populations of <em>Pca </em>display very high genetic variability as demonstrated by the numerous virulence profiles that can be captured during national and international rust surveys. Such levels of polymorphisms likely confer evolutionary advantages to the pathogen and drive adaptation to plant resistance genes deployed in varieties. During the last two decades, <em>Pca</em> populations in the US have undergone drastic virulence shifts yet the underlying genetic and molecular mechanisms responsible for these changes are not understood. Capitalizing on the recent release of two genome references for <em>Pca</em>, a comparative population genomics study of two <em>Pca</em> populations collected in 1990 and 2015, respectively, was launched. Our goal is to determine the population structure and dynamics of <em>Pca</em>, as well as the evolutionary processes that drive virulence changes over time, particularly in response to selective pressures and occurrence of sexual reproduction. Overall, this work contributes to the understanding of the biology of <em>Pca</em> and enables the development of molecular markers associated with rust virulence.</div>